1. Field of the Invention
The present invention relates to a cap device having a torque mechanism for sealing a tank opening with a rotational torque of a predetermined level.
2. Description of the Related Art
One known cap device is a fuel cap for fuel tanks of automobiles (see U.S. Pat. No. 6,076,695). The fuel cap includes a closer to seal a tank opening, a cover with a handle for rotational operations, and a torque mechanism. The torque mechanism includes a coil spring that is located between the cover and the closer, and a click mechanism that includes mating engagement elements respectively formed on the cover and the closer. Coupling of the engagement elements is released to give a click sound, in response to a relative rotation of the cover to the closer by a preset angle.
When the user holds and rotates the handle of the fuel cap in a closing direction to close an inlet opening, the coil spring between the cover and the closer is compressed to transmit a rotational torque from the cover to the closer and accordingly rotate the closer in the closing direction. Coupling of the mating engagement elements of the click mechanism is released to give a click by a rotational torque of or over a preset level. This click sound enables the user to confirm that the closer is clamped with a sealing pressure of or over a preset level.
There are high demands for decreasing the total number of parts and simplifying the structure of the fuel cap.